Process for making tetramethyl lead



United States Patent 3,400,143 PROCESS FOR MAKING TETRAMETHYL LEAD Charles Anthony Sandy, Wilmington, Del., assiguor to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware No Drawing. Filed May 17, 1965, Ser. No. 456,478 Claims. (Cl. 260-437) ABSTRACT OF THE DISCLOSURE Preparation of tetramethyl lead by reaction of monosodium lead alloy with methyl chloride in the presence of ethylenediamine and/or 2-methoxyethylamine as the catalyst. Water and monohydric organic compounds are optional ingredients of the reaction system.

This invention relates to the manufacture of tetramethyl lead, more particularly to its manufacture by the reaction of methyl chloride with monosodium lead alloy in the presence of a novel catalyst system which is highly efiective under mild conditions of temperature and pressure.

Recent trends in the formulation of motor gasoline have created a significant demand for tetramethyl lead as an antiknock agent. However, as disclosed in the recent art, for example by Jarvie et al. in US. Patent 3,048,610, Tullio in U.S. Patents 3,072,694 and 3,072,695, and Cook et al. in US. Patent 3,049,558, the manufacture of tetramethyl lead by the reaction of methyl chloride with monosodium lead alloy presents considerable difiiculties. In direct contrast to the well-known ethyl chloride-monosodium lead alloy system, which does not require catalysis below 100 C. but can be accelerated by ketones, alcohols, esters and other substances known to the art as ethylation accelerators, the methyl chloride-monosodium lead alloy system responds not at all to conditions normally conducive to the formation of tetraethyl lead. In fact, from the disclosures of the recent practitioners of the art, it appears that the methylation of monosodium lead alloy is unique in that only certain metal catalysts have been found to be effective. Such high degree of catalyst specificity appears characteristic also of the mixed methylation-ethylation of monosodium lead alloy as disclosed by Calingaert et al. in US. Patent 2,270,109.

However, such metal catalysts, including the aluminum compounds which have been used commercially, are not entirely satisfactory. They require elevated temperatures at long reaction times, normally temperatures on the order of 100 C. for several hours. Such conditions, in view of the high vapor pressure of methyl chloride, necessitate the use of expensive pressure systems for practical and safe operation. Also, they add to the hazards already inherent in the handling of tetramethyl lead in that they form in the reaction system alkyl aluminum derivatives which are extremely sensitive to air and moisture and tend to ignite spontaneously on exposure to the atmosphere. Also, the reaction masses are sticky and troublesome to discharge from the reactors.

It should be noted that the processes of Jarvie et a1. and Tullio, though providing for relatively smooth and safe initiation of the aluminum-catalyzed system whereby some of the hazards are alleviated, still require rather elevated temperatures for completion of the methylation reaction and do not completely avoid the hazards inherent in handling alkyl aluminum systems.

R. L. Pedrotti and C. A. Sandy, in their copending application, Ser. No. 293,138, filed July 5, 1963, disclose that ammonia is very elfective to catalyze the reaction of methyl chloride with monosodium lead alloy and that its etfectivenes can be enhanced by the presence of certain hydroxylic compounds in small controlled amounts. They disclose that they obtain high yields of tetramethyl lead and can operate successfully at relatively low temperatures. However, ammonia has a tendency to escape from the reaction zone because of its high volatility and hence its use, while eliminating most of the problems and hazards of the prior processes, presents a problem of its own. 011 the other hand, amines in general, such as dimethylamine, trimethylamine, higher alkyl amines and aromatic amines, though less volatile than ammonia, are relatively poor catalysts for this reaction.

Midgley, in US. Patent 1,622,228, discloses the reaction of alkyl halides broadly with active lead compounds,

including sodium lead alloys broadly, in the presence of water or other source of nascent hydrogen plus a catalyst which may be acetamide among other compounds such as NH amines in general, and quaternary ammoniums. The specifically disclosed amines are: aniline, methylaniline, diethylaniline, toluidine, diphenylamine, phenylenediamine, triethylamine, butylamine, amylamine, pyridine, carbazole, piperidine, phenylhydrazine, ammonia, and quinoline. Within the broad disclosure, Na Pb is shown, but not the monosodium lea-d alloy, NaPb. Methyl chloride is broadly included, though not specifically mentioned. With the alkyl chlorides, aniline is preferred. In summary, there is no disclosure of the methyl chloridemonosodium lead alloy system, methoxyethylamine or ethylenediamine as catalysts, or of the use of controlled proportions of amine and hydroxylic compound for advantageous eifects.

Other US. patents, as listed below: 1,559,405, 1,550,- 940, 1,645,389, 1,658,544, 1,661,809, 1,661,810, 1,645,- 390, disclose the use of amines broadly, such as triethylamine pyridine, aniline, and dimenthylaniline in alkylation processes for tetraalkyl lead formation. Like Midgley, they do not suggest or deal with the reaction of methyl chloride with monosodium lead alloy.

It is an object of this invention to provide a new and improved process for the manufacture of tetramethyl lead, particularly one which is adapted for its large scale manufacture. Another object is to effect the reaction of methyl chloride with monosodium lead alloy in an improved manner which overcomes the problems of the prior proceses, i.e. mitigates the fire and explosion hazards inherent in the use of catalyst systems based on aluminum and the problem of the high volatility involved in the use of ammonia. A further object is to provide a catalytic process for reacting methyl chloride with monosodium lead alloy wherein the reaction is initiated smoothly and safely at relatively low temperatures and proceeds rapidly under relatively mild conditions of temperature and pressure to produce tetramethyl lead in high yields. Still another object is to provide such a process which involves the use of a catalyst which does not tend to escape from the reaction mass under reaction conditions. Other objects are to advance the art. Still other objects will appear hereinafter.

The above and other objects of this invention will be accomplished by the process for making tetramethyl lead which comprises reacting monosodium lead alloy with (A) A methylating agent which consists essentially of methyl chloride in the liquid phase, employing at least 1 mole of methyl chloride per mole of alloy;

3 (B) at a temperature of from about 25 C. to about 60 C. (C) in the presence of a catalyst system which consists essentially of ,(a) a catalytically effective amount within the range of from about 0.01 to about 0.5 mole per mole of alloy of at least one amime of the group consisting of ethylenediamine and Z-methoxyethylamine, (b) from to about 0.1 mole of Water per mole of alloy, but not more than 0.3% by weight based on the methyl chloride, and (c) from 0 to about 0.1 mole per mole of alloy of a monohydric organic compound of the formula ROH wherein R represents a member of the group consisting of hydrocarbon and oxahydrocarbon radicals of 1-18 carbon atoms.

In preferred embodiments, the reaction is effected with about 1.3 to about 6 moles of liquid methyl chloride (MeCl) per mole of monosodium lead alloy (NaPb) at from about C. to about 60 C. (corresponding to pressures of from about 100 to about 175 p.s.i.g.). When 2-methoxyethyla'mine is employed as the catalyst, the preferred catalyst system consists essentially of from about 0.1 to about 0.2 mole of said amine and and from about 0.003 to about 0.03 mole of methanol (MeOH) per mole of NaPb, together with such small amounts of water as may be normally present in the methyl chloride and the methanol and cannot be removed therefrom, i.e. of the order of 50 parts per million (p.p.m.) by weight in the methyl chloride and of the order of 240 p.p.m. in the methanol, both of which are generally considered to be substantially anhydrous. The methanol as the catalyst promoter is especially effective at the lower concentrations of 2-methoxyethylamine (about 0.1 mole/mole NaPb and less). When ethylene diamine is employed as the catalyst, the preferred catalyst systems consists essentially of from about 0.01 to about 0.15 mole of substantially anhydrous ethylenediamine per mole of NaPb. Water or monohydric organic compound, as above defined, can be tolerated in the amounts above defined, but they have no detectable beneficial effect and preferably should be avoided or kept below 0.01 mole per mole of NaPb, i.e. the materials employed should be substantially anhydrous and substantially free of hydroxylic organic compounds.

By this process methylation is initiated and brought to completion smoothly and rapidly under mild conditions of temperature and pressure. As illustrated in the examples, the reaction variables (the amount of MeCl, the particular amine and its concentration, the hydroxylic component and its concentration, and the time and temperature of the reaction) are easily coordinated to produce tetramethyl lead rapidly in high yields. At the same time, the hazards involved in handling and processing the aluminum catalysts and the reaction masses produced therefrom are avoided. Thus the manufacture of tetramethyl lead is made more safe, practical and economical. Also, the 2-methoxyethylamine and the ethylenediamine are relatively high boiling and do not tend to escape from the reaction zone under the reaction conditions employed.

The Z-methoxyethylamine and ethylenediamine components of the catalyst system are critical. Without them, practically no tetramethyl lead is produced. Much less effective are the simple alkyl amines, such as ethylamine and propylamine, and aromatic amines, such as aniline and pyridine. It is noteworthy that 3-methoxypropylamine (which differs from Z-methoxyethylamine in having an additional CH group between the MeO and NH groups) is practically without catalytic activity. In view of the above, the pronounced activity of ethylenediamine and 2-methoxyethylamine is believed unobvious and not pre dictable from the behaviour of any known catalyst for this reaction.

Broadly, the quantity of the amine catalyst of this invention will be an amount which will be effective to catalyze the reaction of methyl chloride with monosodium alloy to produce tetramethyl lead, which amount will be in the range of from about 0.01 to about 0.5 mole of said amine per mole of said alloy. The minimum catalytically effective amount and the optimum amounts of said amines Will vary with the reaction variables as pointed out hereinbefore. Ordinarily, the 2-methoxyethylamine will be employed in the range of from about 0.03 to about 0.2 mole per mole of NaPb, preferably from about 0.07 to about 0.2 mole and most preferably at least about 0.1 mole. Also, ordinarily, the ethylenediamine will be employed in the range from about 0.03 to about 0.15 mole per mole of NaPb, most preferably from about 0.07 to about 0.15 mole.

-While the specific amines as defined are critical, water or other hydroxylic compound in controlled proportions can exert marked promotional effects, particularly with the 2-methoxyethylamine, whereby the rate of the methylation reaction and/or its specificity is increased, or the amount of Z methoxyethylamine required is significantly decreased. The toleration of these reaction systems for substantial amounts of water is of further practical importance since these amines (as well as the MeCl) as normally available often contain such amounts of water, the removal of which is tedious and costly.

In contrast to the prior practices regarding the methylation of monosodium lead alloy in the presence of an aluminum based catalyst, it is not critical for practical operation of the process of this invention to exclude or limit moisture to very low levels. This has a commercially impoitant advantage because the methyl chloride ordinarily contains small amounts of water and it is not economically practical to provide completely anhydrous methyl chloride. Methyl chloride, containing 50 p.p.m. or less of water, is generally considered in this art to be substantially anhydrous. For example, in the methylation reaction involving aluminum-type catalysts, it is normally considered desirable to limit the water content of the methyl chloride to less than about 150 p.p.m. water (0.015% wt.) and in general to operate as anhydrously as possible. Substantially larger water levels may, if desired, be present in the methyl chloride according to the present invention, for example on the order of 550 to 3000 p.p.m., 0.05% to 0.3% by weight, provided of course the total water introduced into the reaction mixture does not amount to more than about 0.1 mole per mole of alloy (about 0.77% by weight) and does not exceed about 0.3% by weight of the MeCl. The presence of gross water tends to depress the yields of tetramethyl lead markedly. Preferred water to alloy ratios are in the range 0.00014- 0.03 mole. Based on MeCl, the preferred range is about 50 to about 3000 p.p.m., about 0.005% to about 0.3% by weight, particularly about to about 1000 p.p.m., about 0.01% to about 0.1% by weight.

There may also be used as defined, in conjunction with said water, or alone as the sole catalyst promoter, one or more monohydroxylic organic compounds composed of carbon, hydrogen and one or more oxygens, and containing up to 18 carbon atoms, and no oxygens other than ether and hydroxyl oxygens. In other words, the hydroxylic component need only contain one hydroxyl group and be otherwise essentially inert as far as the alloy is concerned, that is, contain only hydrocarbon and oxyhydrocarbon radicals. Also, the monohydroxylic organic compound can be defined as a compound of the formula RQH'wherein R is a hydrocarbon or an oxahydrocarbon radical of 1-18 carbon atoms, said oxa designation standmg for ether oxygen. Thus, there may be used a variety of aliphatic and cycloaliphatic alcohols consisting of, in addition to said OH group, hydrocarbon or etherhydrocarbon radicals. Similarly, there may be used phenol and phenols containing hydrocarbon and etherhydrocarbon substituents. The activating effect appears to be specific to the monohydroxylic compounds, corresponding polyhydroxylic compounds appearing to have little or no activating or promoting effect.

Representative monohydroxylic organic compounds are the simple alkanols and cyloalkanols such as methanol, ethanol, 1- and 2-propanol, l-butanol, 2-methyl-2- propanol, pentanol, hexanol, 3,5,5-trimethylhexanol, cyclopentanol and cyclohexanol; naturally-occurring fatty alcohols such as the mixtures derived from coconut oil for example and including decanol, dodecanol (lauryl alcohol), tetradecanol (myristyl alcohol), hexadecanol (cecyl alcohol) and octadecanol (stearyl alcohol); alcohols made by the x0 process such as oxo-octyl alcohol and oxo-tridecanol; unsaturated alcohols such as allyl alcohol, oleyl alcohol and proparagyl alcohol; ether alcohols such as ethylene glycol monomethyl ether (methyl Cellosolve), ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, and diethylene glycol monomethl ether; phenolics such as phenol, 0-, mand p-cresol, the xylenols, p-nonly phenol, and resorcinol monomethyl ether. Mixtures of any two or more of the monohydroxylic organic compounds may be used. Methanol or other lower alkanol (of 1-4 carbon atoms) is highly preferred for it is particularly effective as an activator for the 2-methoxyethylamine catalyst both to accelerate the methylation reaction and to favor the formation of tetramethyl lead at the expense of side reactions.

Such monohydroxylic component may be present in molar proportions as high as about 0.1 mole per mole of alloy (about 1.46% by weight of methanol), preferably from about 0.003 to about 0.03 mole per mole of alloy. Also preferably and more usually, the combined (total) amount of water and monohydroxylic organic compound will not exceed about 0.1 mole per mole of alloy.

The term methyl halide methylating agent consisting essentially of methyl chloride includes methyl chloride as the essential source of methyl groups and mixtures thereof with up to about 5 mole percent of methyl iodide based on the methyl chloride. Such small proportions of such methyl iodide tend to promote the amine catalyzed reaction. For example, methyl iodide appears to be particularly effective at low temperatures in conjunction with said amine catalyst to accelerate the methylation reaction and thereby increase the rate of production of tetramethyl lead. While the iodide may be present in small proportions as above, the said amine-catalyzed process appears unique for methyl chloride as the essential methylating agent.

The methylating agent is normally employed in amounts of at least about one mole and usually not more than about 6 moles per mole of alloy. Larger quantities, up to 20 moles, may be used but are not necessary. Preferred ratios are in the range of about 1.3 to about 6 moles of methyl chloride per mole of alloy.

The monosodium lead alloy (NaPb) to be used in this process, i.e. containing 50 mole percent Na and 50 mole percent Pb, or on a weight basis 10% wt. Na and 90% Wt. Pb, has been amply described in the art. It

may be used in various forms, usually comminuted, in-

eluding ground as disclosed by Stecher in U.S.P. 2,134,- 091, flaked as disclosed by Pyk in U.S.P. 2,561,636 or by Tanner in U.S. Patent 2,635,107, and quenched (in MeCl) as described by Mattison in U.S. Patent 2,744,126.

Broadly, the overall process comprises 1) mixing the alloy, methyl chloride, specified amine and, when desired, water or other monohydroxylic catalyst promoter, (2) holding such mixture at a temperature in the range of 0 C. to about 120 C. at which the reaction is initiated and proceeds at a reasonable rate, and (3) recovering the tetra-methyl lead from the reaction mass. Normally, the reaction is effected under agitation and it is usually desirable to effect the reaction in the presence of an inert solid, such as graphite, as an internal lubricant. From about 1% to about 5% by weight of graphite based on the alloy may be used, depending on the dimensions of the reactor, the effectiveness of the agitation means, and the proportions of the reactants. There may also be present a thermal stabilizer for tetramethyl lead, as described in the art by Jarvie et al. in U.S. Patent 3,048,610 and Cook et al. in U.S. Patent 3,049,558, for example a volatile hydrocarbon such as toluene or-isooctane having boiling characteristics comparable to those of tetramethyl lead.

The reactants, catalyst components and other agents (as described above) may be introduced separately or together, all at once or gradually during the course of the reaction. The catalyst components may 'be added as such or in a carrier which conveniently may be the methylating agent or an inert solvent including the themal stabilizers toluene and isooctane.

The reaction mass components may be mixed at low temperatures at which the reaction does not proceed at a substantial rate, e.g., below 0 C. and the mixture then brought to operating temperatures. Or the reactants and other essential components may be brought into contact at temperatures within the operating range, preferably in the preferred 25 C. to 60 C. range. The reaction may be conducted batchwise or continuously.

An important feature of this invention is that the amine-catalyst system effects the methylation reaction at low temperatures and low autogeneous pressures. Reaction mass temperatures are readily controlled by controlling the amount and schedule of catalyst and methyl chloride addition, by cooling where necessary, and by refluxing methyl chloride, to keep the internal pressure at desired levels, sufficient to maintain the methyl chloride in liquid phase or under reflux pressure, for example below 300 p.s.i.g. Indeed, at temperatures of from 25 C. to 60 C., pressures are easily maintained in the 10 0- p.s.i.g. region. Of course, higher pressures may be used, e.g. 1000 p.s.i.g., but are rendered unnecessary by the use of the specified amines in accordance with this invention. The importance of these results is that a greater degree of safety is achieved and at lower operating cost, considering the hazards and expense involved in having a relatively unstable product, such as tetramethyl lead, confined at elevated temperatures.

The resulting reaction mass may be worked up in the usual wavs described in the art. Normally, the residual methyl chloride is vented from the charge at a temperature in the range of about 25 C. to about 60 C., and passed to a recovery system as in tetraethyl lead technology. For this purpose, the temperature of the reaction mixture is adiusted accordingly, if necessary. The tetramethyl lead product is then recovered by solvent extraction. e.g. with toluene, or by steam distillation according to the well known techniques.

In the examples, Y, percent is the percent of the theoretical yield of tetramethyl lead based on the quantitv of alloy employed: C, percent is the total percent of the allov consumed by reaction to produce tetrameth l lead and other products, and Y/C is the ratio of the percent ield of tetramethyl lead (and of the percent of the alloy that is consumed in producing tetramethyl lead) to the total percent alloy consumed in all reactions. Thus, Y/ C is a measure of the reaction specificity to produce tetramethyl lead, the difference between 1.00 and the given values of Y/C, times 100, being the percent allov consumed in side reactions. Also in the examples, TML means tetramethyl lead; MEA means 2-methoxyethvlamine: EDA means ethylenediamine; MeCl means methyl chloride; NaPb means monosodium lead allov; MeOH means methanol; alc. means alcohol; and MeI means methyliodide.

The following examples are given to more fully illustrate the invention, preferred modes of operation 'and the advantageous results to be obtained thereby. The quantities are in parts by weight unless otherwise stated.

Example 1.MEA-catalyzed MeCl-NaPb reaction including promoting efiect of MeOH General procedure.A steel bomb was charged with (a) 100 parts crushed 10 on mesh NaPb enclosed in -a glass ampoule and (b) catalyst components as described below. Th bomb was cooled to 70 0, its atmosphere evacuated and 130 parts MeCl were admitted from a pressurized source, corresponding to a loading density of 0.52 gram MeCl/cc. of bomb capacity. At about 0 C., the closed bomb was struck sharply against a solid object to break the ampoule, placed in a preheated oil bath and its contents vigorously agitated by shaking. Reaction was terminated by cooling to 70 C. and the tetramethyl lead recovered by extracting the reaction mass with toluene.

The MeCl and the MEA utilized were substantially water-free, containing 22 p.p.m. and 240 p.p.m. of water respectively; hence the total water content introduced with these components ranged from about 0.0004 to 0.0005 mole H O/mole NaPb. MeOI-I, where used, was predissolved in the MeCl charge. The promoter concentrations below represent the combined water and methanol contents.

TABLE I [Etiect of MeOCHzCHzNHz (MEA) and MeOH on TML yield in McCl- NaPb reaction] MeCl/NaPb molar ratio=5.0 MEA conc.=as given below MeOH conc.=as given below A. Reaction temp./time=25 C./1 hr.

MEA conc., TML yield, percent (0, percent), promoter concenmole/mole tration, mole/mole NaPb.

NaPb

None 005 01 .015

IIIIIIIIIIII Yb 'IIIIIIIIIIIIII B. Reaction temp.ltime= C./1 hr.

MEA cone, TML yield, percent (C, percent), promoter concenmol lmol tration, mole/mole N aPb.

NaPb 45 None 005 O1 015 .000 Trace (5) .0 26

lncreasing the promoter concentration (MeOI-I) to 0.028 mole/mole NaPb gave essentially the same result, Y=71 at C=84.

2 Increasing reaction time to 1.5 hrs. resulted in Y=84 at 0:94.

Table I (A and B) shows that tetramethyl lead yield increases with increase in catalyst concentration, also in general with increase in promoter concentration. The promoting effect of methanol is particularly pronounced at the lower concentrations of the amine catalyst (the more costly component).

Example 2.Promoting the MEA-cat'alyzed MeCl'NaPb reaction with water Example 3.Effect of miscellaneous promoters of the MBA-catalyzed MeCl-NaPb reaction The process of Example 1 was repeated with MEA as catalyst in the added presence of representative promoters of this invention as tabulated below.

TABLE II MeCl/NaPb molar ratio=5.0 Reaction temp./time=50 C./1 hr.

1 Not counting the almost negligible 0.0004 mole HzO/mole NaPb introduced with McCl (22 ppm).

-Corrcsponds to 0.3 mole percent MeI based on the MeCl.

Comparison with Table 113 shows that allyl alcohol is at least about as effective as MeOH, t-butyl alcohol somewhat less so.

Comparison with Table 1B and Example 2 indicates that 0.1 mole hydroxylic compound (whether as H O or alcohol) is beyond the optimum, though still operable, i.e., etfective to provide improvement over the unpromoted run.

The data taken with that of Example 1 also indicate that the lower limit and optimum amounts of amine may vary, depending on the presence or absence of promoter.

Example 4 The procedure of Example 1 was employed with ethylene-diamine as the catalyst over a range of temperatures and other reaction conditions as tabulated below. In one series (A) the amine contained 1.4% H 0, the MeCl 94 p.p.m. H O. In a second series (B) the water content of the amine was 0.075%, that of the MeCl 23 p.p.m. The total quantity of water introduced is expressed below relative to that of the alloy.

TABLE III [Ethylenediamine (EDA)-catalyzed MeCl-Nalb reaction] MeCl/NaPb molar ratlo=5.0

EDA conc., H20 cone. and reaction temp. as noted below Reaction tnne=1 hr.

1 1.5 hours reaction time.

EDA is somewhat more etfective in the presence of the more limited amounts of water. At the relatively higher temperatures, hydroxyl compound may be harmful.

Example 5 Employing the conditions and procedure of Example 1, the catalysts of this invention are compared with various other amines which include representative amines proposed by the prior art as catalysts for the reaction of alkyl halides generally with sodium lead alloys broadly but not with monosodium lead alloy specifically. Th results are shown in Table IV.

TABLE IV [Amine-catalyzed CHSCI-NaPb reaction] CH3Cl/NaPb molar ratio=5.9 Amine cone, H2O cone, and reaction temp. are noted below; Reaction timo=1 hour.

Catalyst Mole catalyst/ Mole H20] Temp, 0. Percent Percent O Y/C mole NaPb mole N aPb M Yield Ethylene diamine 035 0031 25 72 77 93 069 0047 25 84 94 90 135 0078 25 82 92 90 153 0087 85 35 37 94 Z-methoxyethylamine 123 0015 25 80 89 90 Diethylamine 204 0015 25 16 0 204 0015 110 2 18 l4 Trimethylamino 150 0015 25 1 9 l5 Ethylamine 204 0015 85 2 26 7 I 204 0015 25 3 12 21 n-Butylamine 126 0015 25 3 12 23 .126 0015 110 13- 49 26 Pyridine.- 116 0015 25 3 8 31 Aniline 099 0015 25 0 15 0 099 0015 110 11 26 43 1,2-diamino-propane 124 0015 25 15 25 58 124 0015 85 25 36 1,3-diamino-propane 124 0015 85 4 26 S-methoxy propylamine 052 I 0051 5 It will be apparent that the amines, other than the '2-methoxyethylamine and the ethylenediamine of this invention, have little or no catalytic effect on.the reaction of methyl chloride'with the monosodium lead alloy and hence, at best, are very poor catalysts for that reaction.

It will be understood that the foregoing examples are given for illustrative purposes solely and that this invention is not limited to the specific embodiments described therein. On the other hand, it will be readily apparent to those skilled in the art that, subject to the limitations set forth in the general description, many variations can be made in the proportions, conditions, promoters and pro cedures employed without departing from the spirit and scope of this invention.

From the foregoing description and examples, it will be apparent that this invention provides a new and improved process for the manufacture of tetramcthyl lead which overcomes the problems of the processes of the prior art. Particularly, the process of this invention enables the production of tetramethyl lead in a relatively safe and rapid manner under mild conditions. The process is simple and economical to operate. Thus, it -is apparent that this invention, constitutes a valuable advance inand contribution' to the art.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. The process for making tetramethyl lead which comprises reacting monosodium lead alloy with (A) a methylatingagent which consists essentially of methyl chloride in the liquid phase, employing at least 1 mole of methyl chloride per mole of alloy;

(B) at a temperature of from about 25f C. to about 60 C. (C) in the presence of a catalyst system which cons'ists essentially of 1 v (a)"a catalytically effective amount within the range-of-frorn about-0.01 to about 0.5 mole per mole of alloy of at least one amine of the group consisting-of ethylenediamine and 2-methoxyethylamine, I (b) from 0 to about 0.1 mole of water per mole of alloy, but not more than 0.3% by weight based on the methyl chloride, and 1 (c) from 0 to about 0.1 mole per mole of alloy of a monohydric organic compound of the formula ROH wherein R represents a member of the group consisting of hydrocarbon and oxahydrocarbon radicals of 1-l8 carbon atoms.

2. The process for making tetramethyl lead which comprises reacting monosodium lead alloy with (A) a methylating agent which consists essentially of methyl chloride in the liquid phase, employing at least 1 mole of methyl chloride per mole of alloy;

(B) at a temperature of from about 25 C. to about a (C) in the presence of a catalyst system which consists essentially of (a) a catalytically effective amount within the range of from about 0.01 to about 0.5 mole of 2-methoxyethylamine per mole of alloy;

(b) from 0 to about 0.1 mole of water per mole of alloy, but not more than 0.3% -by weight based on the methyl chloride, and

(c) from 0 to about 0.1 mole per mole of alloy of a monohydric organic compound of the formula ROH wherein R represents a member of the group consisting of hydrocarbon and oxahydrocarbon radicals of 1-18 carbon atoms.

3. The process for making tetramethyl lead which comprises reacting monosodium lead alloy with (A) a methylating agent which consists essentially of methyl chloride in the liquid phase, employing from 1 to about 6 moles of methyl chloride per mole of (B) at a temperature of from about 25 C. to about 60 C. (C) in the presence of a catalyst system which consists essentially of (a) a catalytically effective amount within the range of from about 0.03 to about 0.2 mole of Z-methoxyethylamine per mole of alloy,

(b) from about 0.003 to about 0.03 mole of water per mole of alloy, but not more than 0.3% by weight based on the mthyl chloride, and

(c) from 0 to about 0.03 mole per mole of alloy of a monohydric organic compound of the formula ROH wherein R represents a member of the group consisting of hydrocarbon and oxahydrn carbon radicals of 1-18 carbon atoms.

4. The process for making tetramethyl lead which comprises reacting monosodium lead alloy with (A) a methylating agent which consists essentially of methyl chloride in the liquid phase, employing from 1 to about 6 moles of methyl chloride per mole of alloy;

(B) at a temperature of from about 25 C. to about 60 C.

(C) in the presence of a catalyst system which consists essentially of (a) a catalytically effective amount within the range of from about 0.07 to about 0.2 mole of Z-methoxyethylamine per mole of alloy,

(b) from about 0.0004 to about 0.03 mole of water per mole of alloy, but not more than 0.3% by weight based on the methyl chloride.

5. The process for making tetramethyl lead which comprises reacting monosodium lead alloy with (A) a methylating agent which consists essentially of methyl chloride in the liquid phase, employing from 1 to about 6 moles of methyl chloride per mole of alloy;

(B) at a temperature of from about 25 C. to about (C) in the presence of a catalyst system which consists essentially of (a) a catalytically effective amount within the range of from about 0.03 to about 0.2 mole of 2-methoxyethylamine per mole of alloy;

(b) from to about 0.3 mole of water per mole of alloy, but not more than 0.3% by weight based on the methyl chloride, and

(c) from about 0.003 to about 0.03 mole per mole of alloy of a monohydric organic compound of the formula ROH wherein R represents a member of the group consiting of hydrocarbon and oxahydrocarbon radicals of 1-18 carbon atoms.

6. The process for making tetramethyl lead which com prises reacting monosodium lead alloy with (A) a methylating agent which consists essentially of methyl chloride in the liquid phase, employing from 1 to about 6 moles of methyl chloride per mole of alloy;

(B) at a temperature of from about C. to about (C) in the presence of a catalyst system which consists essentially of (a) a catalytically effective amount within the range of from about 0.03 to about 0.2 mole of Z-methoxyethylamine per mole of alloy;

(b) from 0 to about 0.3 mole of water per mole of alloy, but not more than 0.3% by weight based on the methyl chloride, and

(c) from about 0.003 to about 0.03 mole of methanol per mole of alloy.

7. The process for making tetramethyl lead which comprises reacting monosodium lead alloy with (A) a methylating agent which consists essentially of methyl chloride in the liquid phase, employing from 1 to about 6 moles of methyl chloride per mole of alloy;

(B) at a temperature of from about 25 C. to about (C) in the presence of a catalyst system which consists essentially of (a) a catalytically effective amount within the range of from about 0.07 to about 0.2 mole of 2-methoxyethylamine per mole of alloy;

(b) from 0 to about 0.03 mole of water per mole of alloy, but not more than 0.3% by weight based on the methyl chloride, and

(c) from about 0.003 to about 0.03 mole of methanol per mole of alloy.

8. The process for making tetramethyl lead which comprises reacting monosodium lead alloy with (A) a methylating agent which consists essentially of methyl chloride in the liquid phase, employing from 1 to about 6 moles of methyl chloride per mole of alloy; (B) at a temperature of from about 25 C. to about (C) in the presence of a catalyst system which consists essentially of (a) a catalytically effective amount within the range of from about 0.07 to about 0.15 mole of 2-methoxyethylamine per mole of alloy;

(b) from 0 to about 0.001 mole of water per mole of alloy, but not more than 0.3% by Weight based on the methyl chloride, and

(c) from about 0.003 to about 0.03 mole of methanol per mole of alloy.

9. The process for making tetramethyl lead which comprises reacting monosodium lead alloy with (A) a methylating agent which consists essentially of methyl chloride in the liquid phase, employing at least 1 mole of methyl chloride per mole of alloy;

(B) at a temperature of from about 25 C. to about (C) in the presence of a catalyst system which consists essentially of (a) a catalytically etfective amount within the range of from about 0.01 to about 0.5 mole of ethylenediamine per mole of alloy,

(b) from 0 to about 0.01 mole of water per mole of alloy, but not more than 0.3% by weight based on the methyl chloride, and

(c) from 0 to about 0.01 mole per mole of alloy of a monohydric organic compound of the formula ROH wherein R represents a member of the group consisting of hydrocarbon and oxahydrocrabon radicals of 1-18 carbon atoms.

10. The process for making tetramethyl lead which comprises reacting monosodium lead alloy with (A) a methylating agent which consists essentially of methyl chloride in the liquid phase, employing from 1 to about 6 moles of methyl chloride per mole of alloy;

(B) at a temperature of from about 25 C. to about (C) in the presence of a catalyst system which consists essentially of (a) a catalytically effective amount within the range of from about 0.07 to about 0.15 mole of ethylenediamine per mole of alloy,

(b) from 0 to about 0.001 mole of water per mole of alloy, but not more than 0.3% by weight based on the methyl chloride, and

(c) from 0 to about 0.001 mole per mole of alloy of a monohydric organic compound of the formula ROH wherein R represents a member of the group consisting of hydrocarbon and oxahydrocarbon radicals of 1-18 carbon atoms.

References Cited UNITED STATES PATENTS 1,559,405 10/ 1925 Calcott 260-437 1,622,228 3/ 1927 Midgley 260-437 1,621,809 3/1928 Monroe 260-437 1,717,961 6/1929 Daudt 260-437 2,635,106 4/1953 Shapiro et a1 260-437 3,188,334 6/1965 Beaird et al. 260-437 3,281,442 10/ 1966 Pedrotti et al 260-437 TOBIAS E. LEVOW, Primary Examiner.

H. M. S. SNEED, Assistant Examiner.

U.S. DEPARTMENT OF COMMERCE PATENT OFFICE Washington, D.C. 20231 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 ,400 ,143 September 3 1968 Charles Anthony Sandy It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 10, line 4l, after "of", second occurrence, insert alloy; line 51, "mthy1 should read methyl Signed and sealed this 3rd day of February 1970.

(SEAL) Attest:

WILLIAM E. SCHUYLER, JR.

Edward M. Fletcher, Jr.

Attesting Officer Commissioner of Patents 

